Type-Length-Value

A form of encoding that generally conforms to the following format:

       0                   1                   2                   3
       0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
      |     Type      |    Length     |              ...              |
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
      ~                              ...                              ~
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

     Type           8-bit identifier of the type of option.  The
                    value in the Type field is context dependent. 

     Length         8-bit unsigned integer.  The length of the option
                    (including the type and length fields) in units of
                    8 octets.  
                    A  Length value of 0 is often either invalid or 
                    indicates a minimum value of, for example, 64bits.  

      Value         This is a variable length field (as specified in
                    the Length field) containing context-specific 
                    values.